1. Field of the Invention
The preferred embodiments of present invention relate generally to, among other things, internal combustion engines and, more particularly, to internal combustion engines employing internal exhaust gas recirculation (EGR).
2. Discussion of the Background
Many modern vehicles are turning to the implementation of exhaust gas recirculation in which, e.g., exhaust gasses are cooled and burned again to achieve lower chemical emission levels. A number of known systems and methods are illustrated, by way of example, in the patents discussed below.
U.S. Pat. No. 6,470,864, the disclosure of which is incorporated herein by reference in its entirety (e.g., for background), and which is also assigned to the present assignee, Mack Trucks, Inc., shows a Turbocharged Engine with Exhaust Gas Recirculation (EGR), including, among other things, an EGR cooler.
U.S. Pat. No. 6,378,515, the disclosure of which is incorporated herein by reference in its entirety (e.g., for background), and which is also assigned to the present assignee, Mack Trucks, Inc., shows an Exhaust Gas Recirculation Apparatus And Method including, among other things, an EGR controller.
U.S. Pat. No. 6,336,447, the disclosure of which is incorporated herein by reference in its entirety (e.g., for background), and which is also assigned to the present assignee, Mack Trucks, Inc., shows a method and apparatus for compression brake enhancement using fuel and an intercooler bypass.
U.S. Pat. No. 6,273,076, the disclosure of which is incorporated herein by reference in its entirety (e.g., for background), states that an “object of the invention is to optimize the performance of a compression ignition internal combustion engine by . . . control of the excess air/fuel ratio and/or intake air charge temperature.” Col. 4, line 8+.
U.S. Pat. No. 5,385,019, the disclosure of which is incorporated herein by reference in its entirety (e.g., for background), shows compression release engine braking methods and apparatus for use with turbocharged engines having intercoolers. See also Col. 2, line 1+.
U.S. Pat. No. 4,385,496 indicates that it shows “an intake system for an internal combustion engine having a supercharger [having] a first air passage and a second air passage each for conducting air from the supercharger to the engine.” See Abstract. The '496 patent further indicates that “[t]he second air passage leads the air directly from the supercharger to the engine without cooling the air.” See col. 1, line 42+.
U.S. Pat. No. 3,894,392 indicates that it shows a supercharged diesel engine having “a by-pass pipe . . . arranged in parallel with [a] cooler” and that “during the period of starting and of raising the temperature of the engine, a portion at least of the air delivered by the compressor passes through the by-pass pipe.” See col. 1, lines 41+.
While a variety of exhaust gas recirculation systems and methods are known, there remains a need for new and improved systems and methods.